Bernie Masters is a geologist/zoologist who spent 8 years as a member of the Western Australian Parliament. Married to Carolina since 1976 and living in south west WA, Bernie is involved in many community groups. This blog offers insights into politics, the environment and other issues that annoy or interest him. For something completely different, visit www.fiatechnology.com.au for information about vegetated floating islands - the natural way to improve water quality.

Friday, May 26, 2017

Why Are Green Buildings So Inefficient in Their Energy Usage?

Why Don’t Green Buildings Live Up to Hype on Energy Efficiency?

Analysts call it the “energy performance gap” — the difference
between promised energy savings in green buildings and the actual
savings delivered. The problem, researchers say, is inept modeling
systems that fail to capture how buildings really work.

Not long ago in the southwest of England, a local community set out
to replace a 1960s-vintage school with a new building using triple-pane
windows and super-insulated walls to achieve the highest possible energy
efficiency. The new school proudly opened on the same site as the old
one, with the same number of students, and the same head person—and was
soon burning more energy in a month than the old building had in a year.

The underfloor heating system in the new building was so badly
designed that the windows automatically opened to dump heat several
times a day even in winter. A camera in the parking lot somehow got
wired as if it were a thermal sensor, and put out a call for energy any
time anything passed in front of the lens. It was “a catalogue of
disasters,” according to David Coley, a University of Bath specialist
who came in to investigate.

Many of the disasters were traceable to the building energy model, a
software simulation of energy use that is a critical step in designing
any building intended to be green. Among other errors, the designers had
extrapolated their plan from a simplified model of an isolated
classroom set in a flat landscape, with full sun for much of the day.
That dictated window tinting and shading to reduce solar gain. Nobody
seems to have noticed that the new school actually stood in a valley
surrounded by shade trees and needed all the solar gain it could get.
The classrooms were so dark the lights had to be on all day.

It was an extreme case. But it was also a good example, according to
Coley, of how overly optimistic energy modeling helps cause the “energy
performance gap,” a problem that has become frustratingly familiar in
green building projects. The performance gap refers to the failure of
energy improvements, often undertaken at great expense, to deliver some
(or occasionally all) of the promised savings. A study
last year of refurbished apartment buildings in Germany, for instance,
found that they missed the predicted energy savings by anywhere from 5
to 28 percent. In Britain, an evaluation
of 50 “leading-edge modern buildings,” from supermarkets to health care
centers, reported that they “were routinely using up to 3.5 times more
energy than their design had allowed for” — and producing on average 3.8
times the predicted carbon emissions

Buildings account for 40 percent of climate change emissions and are the fastest growing source of emissions.

The performance gap is “a vast, terrible enormous problem,” in the
words of one building technology specialist, and that’s not an
exaggeration. Though much of the public concern about energy
consumption and climate change focuses on automotive miles-per-gallon,
the entire transport sector — including trains, planes, ships, trucks,
and cars — accounts for just 26 percent of U.S. climate change
emissions. Buildings come in at 40 percent, and they are the fastest
growing source of emissions, according to the U.S. Green Building
Council.

Eliminating the performance gap matters particularly for European Union nations, which have a legally binding commitment to reduce emissions by 80 to 95 percent below 1990 levels
by mid-century. But knowing with confidence what savings will result
matters for anybody trying to figure out how much to invest in a
particular energy improvement.

Researchers have generally blamed the performance gap on careless
work by builders, overly complicated energy-saving technology, or the
bad behaviors of the eventual occupants of a building. But in a new study,
Coley and his co-authors put much of the blame on inept energy
modeling. The title of the study asks the provocative question “Are
Modelers Literate?” Even more provocatively, a press release
from the University of Bath likens the misleading claims about building
energy performance to the Volkswagen emissions scandal, in which actual
emissions from diesel engine cars were up to 40 times higher than “the
performance promised by the car manufacturer.”

For their study, Coley and his co-authors surveyed 108 building
industry professionals — architects, engineers, and energy consultants —
who routinely use energy performance models. To keep the problem
simple, the researchers asked participants to look at a typical British
semi-detached home recently updated to meet current building codes. Then
they asked test subjects to rank which improvements made the most
difference to energy performance. Their answers had little correlation
with objective reality, as determined by a study monitoring the actual
energy performance of that home hour-by-hour over the course of a year. A
quarter of the test subjects made judgments “that appeared worse than a
person responding at random,” according to the study, which concluded
that the sample of modelers, “and by implication the population of
building modelers, cannot be considered modeling literate.”

‘We have cases where modelers
will come up with a savings measure that is more than the energy use of
the house,’ says one scientist.

Predictably, that conclusion raised hackles. “The sample seems odd to
me,” said Evan Mills, a building technology specialist at Lawrence
Berkeley National Laboratory, “to include so many people who are junior
in the practice, and then to be criticizing the industry at large.” He
noted that almost two-thirds of the 108 test subjects had five years or
less experience in construction. But Coley and his co-authors found
that even test subjects with “higher-level qualifications, or having
many years of experience in modeling,” were no more accurate than their
juniors.

In any case, Mills acknowledged, “the performance gap is real, and we
must be aware of models not properly capturing things. We have cases
where modelers will come up with a savings measure that is more than the
energy use of the house, because they are just working with the model,”
and not paying attention to the real house.

That sort of problem — energy models showing unreasonable results —
also turns up at the preliminary stage on 50 percent of projects going
through the LEED certification process, said Gail Hampsmire of the U.S.
Green Building Council. Designers have a tendency to take a “black
box” approach, providing whatever inputs a particular energy model
requires and then accepting the outputs “without evaluating the
reasonability of those results,” she said. “You always have the issue of
garbage in/garbage out, and the capability of the modeler to identify
whether they are getting garbage out is critical.”

So what’s the fix? The current accreditation requirements for energy
modelers are “very gentle,” said Coley, but “when you’re trying to get
something off the ground relatively quickly, you can’t send everybody
back to college for three years.” In any case, the problem isn’t really
education in the formal sense.

“It has to do with feedback,” he said, or the lack of it. The culture
of building construction says it’s perfectly reasonable for architects —
but not energy modelers —to travel hundreds of miles to see how the
actual building compares with what they designed. For energy modelers,
there’s not even an expectation that they’ll get on the phone with the
building manager at year one and ask how energy usage compares with the
original model. As a result, said Coley, energy modeling can become like
theoretical physics: “You can very easily create a whole web of
theories, and then you find yourself studying the physics of your
theories, not the physics of the real world.”

The organization that gives LEED certification is now requiring that developers post actual energy usage on an online data base.

The answer, he suggested, is a regulatory requirement that modelers
follow up on their work by routinely checking their predictions against a
building’s actual energy consumption. A system of modest inducements
could also make that feedback more broadly available — for instance, by
promising to take three weeks off the planning permissions process for
developers who commit to posting actual energy usage to an online
database. The Green Building Council has begun to require that sort of
reporting for projects seeking LEED certification, said Hampsmire, with
an online platform now in development “for building owners to track
their own performance and compare it with other buildings.”

A second problem, according to Coley, is the tendency of government
agencies to require simplified energy models at the start of the design
process. The requirements often include certain uniform assumptions
about energy use, making it easier to compare one building with
another. “Because you have to do that at the start, it becomes the
default, and this sets up a kind of ‘Alice in Wonderland’ world, and
it’s not surprising that modelers model this artificial world.” But at
least in the United States that has become less of a problem in recent
years, according to Hampsmire. Current building code requirements are
“fairly good,” she said. “They don’t say, ‘Model energy use for a
building occupied eight hours a day,’” or some other arbitrary standard.
Instead, “they specifically state that all energy use has to be modeled
as anticipated.”

The takeaway from all this isn’t to discredit energy modeling but to
improve it. Builders increasingly need realistic modeling, said Coley,
by people with a deep knowledge of building physics and at least as much
experience with real buildings as with energy models. Without that, the
result will be even more $500-million office blocks with too much glass
on the southern exposure, causing everybody inside to bake on a hot
summer afternoon. Without smart energy modeling, the result will be a
world spinning even faster into out-of-control climate change.

“This isn’t rocket science,” said the Berkeley Laboratory’s Mills. But then he added, “It’s harder than rocket science.”

Richard Conniff is a National Magazine Award-winning writer whose articles have appeared in The New York Times, Smithsonian, The Atlantic, National Geographic, and other publications. His latest book is House of Lost Worlds: Dinosaurs, Dynasties, and the Story of Life on Earth. He is a frequent contributor to Yale Environment 360.